(1) Field of the Invention
The present invention relates to a camera system which electronically stores an image of an object and displays the image on a display monitor.
(2) Description of the Related Art
Generally, to achieve an adequately high level of resolution of an image captured by using a digital camera or a video camera, it is necessary to use a zoom-up function of the camera or move the camera close to an object to be imaged. This makes it difficult to obtain an image covering a wide angle related to the object. To capture an image covering a wide angle related to the object, it is necessary to use a zoom-down function of the camera or move the camera away from the object. However, this makes it difficult to obtain an image with a high level of resolution.
In order to obtain a wide-angle image with a high resolution from an object, a divisional shooting method has been proposed. In the divisional shooting method, a plurality of partially overlapping images are successively shot so as to cover a wide angle related to the object, and they are synthesized to create a composite image with an adequate level of resolution.
As disclosed in Japanese Published Utility Model Application No. 8-4783, an image processing device which is capable of combining a plurality of partially overlapping images together to create a composite image is known.
To effectively carry out the divisional shooting method, it is necessary that, after a preceding image is taken and before a current image is taken, the user stop movement of an optical axis of the camera at an appropriate position where an overlapping portion of the two adjacent images is appropriate for subsequently producing a composite image from the images. However, in order to meet this requirement, a conventional digital camera requires a special adapter. If such an adapter is not used, it is difficult for the conventional digital camera to effectively carry out the divisional shooting method. In a case of the conventional digital camera with no special adapter, there is a possibility that no overlapping portion exists between the two adjacent images or a too large overlapping portion be produced between the two adjacent images. If the overlapping images with undesired overlapping portions are obtained through the divisional shooting method, it is difficult to effectively combine or synthesize the images together to create a composite image.
An object of the present invention is to provide a camera system which displays an image indicating a positional relation among partially overlapping images, and enables an operator to easily and effectively carry out a divisional shooting process.
Another object of the present invention is to provide a divisional shooting method which displays an image indicating a positional relation among partially overlapping images on a screen of a monitor during a divisional shooting mode of a camera system.
The above-mentioned objects of the present invention are achieved by a camera system which comprises: a display monitor which displays an image of an object, taken by an optical unit, on a screen of the monitor; a reading unit which reads a preceding image and a current image among a plurality of partially overlapping images, from a memory device, the preceding image and the current image containing a common element; a determining unit which determines a positional relation between the preceding image and the current image based on a common pattern derived from the common element in the two adjacent images read by the reading unit; and a displaying unit which displays an image indicating a boundary of the preceding image on the screen of the monitor at a shifted position according to the positional relation determined by the determining unit, with the current image concurrently displayed on the screen of the monitor.
The above-mentioned objects of the present invention are achieved by a divisional shooting method for a camera system in which at least two of partially overlapping images of an object, taken by an optical unit, are displayed, comprising the steps of: reading a preceding image and a current image among the partially overlapping images, from a memory device, the preceding image and the current image containing a common element; determining a positional relation between the preceding image and the current image based on a common pattern derived from the common element in the two adjacent images; and displaying an image, indicating a boundary of the preceding image, on a screen of a display monitor at a shifted position according to the positional relation determined by the determining step, with the current image concurrently displayed on the screen of the monitor.
In the camera system of the present invention, a positional relation between the preceding image and the current image is determined based on a common pattern derived from the common element in the two adjacent images. The operator can easily carry out a divisional shooting mode of the camera system by viewing both the current image and the image indicating the positional relation between the partially overlapping images on the screen of the monitor. The positional relation between the preceding image and the current image is clearly noticeable to the operator by viewing the positional relation image on the screen of the monitor together with the current image while the camera is panned in a desired direction. Therefore, the operator easily stops the movement of the optical axis of the camera at an appropriate position by viewing the positional relation image on the screen of the monitor, and turns ON a shutter switch to store the current image.